The findings of the Canadian study indicate that those in the age group of eight to 16 are not only vulnerable to concussions but -- because their brain is still developing -- they are neurologically more fragile than adults for performing tasks that require cognitive motor integration following a concussion.

After a concussion, young athletes usually rejoin their teams in a few weeks if they do not have any active symptoms. "However, they may take up to two years to fully recover from the injury before they can play as skillfully as their teammates with no history of concussion," said Lauren Sergio from York University in Canada.

"Performing motor tasks, guided by what we see, is crucial in skill-based activities such as sports," Sergio added in the paper published in the journal Concussion.

The team analysed the prolonged difficulty in cognitive-motor integration in 50 children and adolescents with a history of concussion and were compared with 49 who have never had a concussion.

The participants in both the groups were asked to perform two different tasks on a dual-touchscreen laptop. In one task, target location and motor action were aligned.

In the other task that tested cognitive-motor integration, the required movement was not aligned with the guiding visual target and required simultaneous thinking for successful performance.

"We noticed significant difficulty in completing the tasks among those with concussion history," said lead author Marc Dalecki."In fact, it took many of the children two years after the concussion to have a similar performance on the task as children who did not have a history of concussion," Dalecki noted.

"The current return to sport assessment doesn't test to see if the injured person has regained this ability. Because of this, often children and youth who have had a concussion end up returning to normal activities before they are fully recovered which makes them more vulnerable to another concussion," Sergio said.